In order to strongly fix two elements to each other, a metallic fastening member such as a screw and a bolt is used. At such a time, it may be necessary to secure electrical insulation between the two elements.
PTL 1 describes an insulating spacer for insulating an electronic apparatus and a metal frame from each other when the electronic apparatus is fastened and fixed to the metal frame with a metal screw. PTL 1 describes an example in which a metal frame is sandwiched between two divided insulating collars, an example in which an insulating spacer having an elastic part whose diameter is increased when a metal screw is inserted, and the like, as the prior art, and indicates that the shapes of them are larger than the outer diameter of the metal screw. Then, PTL 1 discloses an insulating spacer including a plurality of elastic thin base supports and clipping portions each of which is provided at the tip of each of the base supports. The base supports, which are apart from each other, are arranged upright from an insulating base portion. The clipping portions sandwich the shaft part of a metal screw. In any of these examples, a head part of the metal screw is exposed from an insulator.